Carburetor



Dec. 5, 1933. A. MATHn-:u 1,937,830

CARBURETOR Patented Dec. 5, 1933 Y 1,937,830 oARBUREToR Andr Mathieu,Brussels, Belgium Application June l15, 1931, Serial No. 544,662, i andin Belgium June 23, 1930` 18 Claims.

`This invention concerns a carburetor whereby light or heavy liquidfuels may be gasied for feeding, in particular, internal combustionengines under conditions ensuring a very low fuel consumption. T

According to the invention, the air to be car- `bureted sucks from aring shaped aperture, sur-- rounding the apex of an inverted cone orlike convex body, a thin annulus of fuel which it carries upwards,whilst spreadingthe same upon the flaring surface of the cone in `a filmof progressively diminishing thickness, which it absorbs by contact.VThe air to be carbureted is preferably divided into two concentricstreams of which the inner stream, of small, cross-section,

impinges at high speed against the apex of the `said cone to suck up thefuel, whilst the outer or peripheral stream joins the central or innerstream beyond the apex and sweeps the surface of-said cone, togetherwith the inner stream. Carbureting His then controlled, during normalrunning of the motor, by throttling or releasing both concentric streamsof air simultaneously whilst, during slow or idle running, the outer orperipheral air `stream is entirely cut off. It may in some cases bedesirable to cause the .air which sweeps the `spreader cone to bewhirled.

In a carburetor constructed to embody the principlesfof said process,the inverted cone is tted above a jet fed from a constant level chamberorotherwise, the mouth of said jet surrounding the apex of the cone andopening axially inside theconstriction of a choke tube. The delivery offuel from the jet is regulated by moving the apex of the cone inwards oroutwards of the jet mouth, whilst the air `supply to the choketube iscontrolled by means of a conical valve surrounding the jet and mountedto slide axially. `Said inlet valve is connected with an outlet valveadapted to` move simultaneously therewith, to control the vacuum at theoutlet of the choke tube, said outlet valve also acting as a deflectorof the air and fuel mixture.

The air to be carbureted may beadmitted within the choke tube around theinlet valve only, but it is preferable to admit it both around said'valve and through the same, in order to divide the air into twoconcentric streams, as stated above. In this case, the conical valve istubular vin shape and its truncated apex coacts with the `point of thespreader cone to throttle the inner, central' or primary air stream,whilst its dished base throttles the outer; peripheral or secondary airstream by obstructing the choke tube inlet. For slow or idle running ofthe motor, the valve (Cl. E61-49) closes the secondary air inletcompletely and only allows the passage of the quantity of primary airwhich is essential for continued withdrawal of fuel from the jet.

The outlet valve, which moves jointly with th inlet valve, mayfurthermoremove towards the choke tube independently of the inletvalveso that,`if back-firing takes place at the carburetor, said outletvalve is impelled by the pressure of the ignited gasto close the choketube outlet and 65 thus prevent the flame from spreading Within thecarburetor. On the other hand, to avoid useless fuel consumption whenthe motor revolves idly at high speed, when running downhill forinstance, the jet is fitted with a valve, 79 actuated by thevacuumobtaining in the motor induction manifold, to cut off the fuelfeedto the jet as soon as said Vacuum exceeds a predetermined value.

The abovementioned features of the invention 75 and some others will nowbe described with refervence to the accompanying drawing which shows,

by way of example, one constructional embodiment of the carburetor.

Fig. 1 is a vertical section of the carburetor, 89 partly in sideelevation, the parts being in the slow or idle running positions;

Fig. 2 is a partial View of Fig.v 1, showing the inlet valve fullyopened;

Fig. 3 is a vertical section of the jet, showing 8,5 the consumptionrestricting valve in its closed positionfor idle running; i

Fig. 4 is a cross section of a further detail.

In said drawing, 1 is the inverted or spreader cone whose apex 2 entersthe centre of the mouth 90 3of jet 4, and 5 is the choke tubesurrounding these members. The inlet to `choke tube 5 is `controlled bya conical tubular valvev6, `axially slidable round jet 4 and connectedwith an outlet deflector-valve 8, fitted within an auxiliary/choke 95tube 9 constituting an extension of choke tube 5. All these members arecontained in a housing, the upper part 12 of which forms a reheatingjacket surrounding the choke tubes. The lower portion 13 of said housingforms a constant-level cham- 100 ber for the fuel to feed jet 4. Aring-shaped float 14, controlling the inlet valve 15 of Said chamber, soregulates the fuel level that it is flush with mouth 3 of the jet.

The constant-level chamber 13 is connected 105 with jet 4 by means ofducts 23,drilled through the arms 24 of a cruciform member, integralwith the chamber walls, said ducts opening in a central space 25, whichis closed by means of a screw-plug 26 and contains a ball 28 and aspring .110

27 adapted to apply the latter against the mouths of ducts 23 and toocclude them when the jet is dismounted. The ball 28 is normally heldclear of its seating by a tubular screw 28, screwed within jet 4, andfuel may ascend in the jet by entering the tubular screw through slots30 in the base of the same, passing through a sleeve 31 fitted slidablyin the jet and streaming towards the annular mouth3 of the jet throughports 32, provided in the wall of said sleeve.

The upper portion 31 of sleeve 31 which is made integral with the point2 of the spreader cone 1, is constricted in order to provide therequisite space between itself and the jet for the ow of fuel towardsmouth 3. As they drawing shows, the point 2 is not even but comprises apoint-stem 2a from which it is separated by an acutely angled groove 33.The conicity of the point-stem 2a. is more acute than that of point 2and, hence, than that of cone 1 and is preferably so calculated thatextensions of its sides would `intersect the walls of cone l at thepoint where the latter joins point 2, the shoulder constituted by groove5 being substantially flush with the lip of jet mouth 3. The section ofthe annular mouth 3 and consequently the fuel supply from the jet areregulated by lifting the latter from its conical seating 34 and byscrewing or unscrewing the tubular screw 29 to a varying degree withinthe jet, according to the adjustment required, thereby mowing towards oraway from mouth 3 the point-stem 2a, which acts as a needle and to whichthe motion of screw 29 is transmitted by sleeve 3l. A spring 35,contained within cone l, bears against point 2 through a sleeve 36 andpresses said point downwards, together with sleeve 31, to hold thelatter in contact with screw 29.

The other end of the spring 35Ybears against a threaded ring 37, screwedwithin a tube. 38,'which forms an upward extension of the conical valve6 and carries the deilector valve 8. Tube 38 passes smoothly through acentral bore of the spreader cone 1, within which it is adapted to slideround sleeve 36 and point 2, carrying with it the two valves 6 and 8 ofwhich the latter is pressed against a rim 40 of ring 37, screwed withinsaid tube. Ring 37 is integral with and is surmounted by a stirrup piece41, carrying a roller 42 against which bears a control lever 43actuated, through arod 44, for example, by the accelerator pedal of theengine. Y

When said lever 43 depresses roller 42, the tube 38 and both valves 6and 8 move downwards, cornpress spring 35, bearing against stationarysleeve 36, and place themselves either in the full-open valve positionshown in dots and dashes in Fig. 1 and in full lines in Fig. 2, or in anintermediate position dependent upon the amount of movement imparted tolever 43. Upon said lever being released, spring 35- returns the tubeand valves to the closed position.

A plurality of elongated ports 45, provided at the base of tube 88, areso occhi-ded by cone 1, when the valves are in the closed position, thatonly a small portion of their lower ends remain open. They are uncoveredwhen the tube emerges from the cone and open progressively, as thevalves approach their full open position. Tof gether with valves 6 and8, said ports control the action of the carburetor and the richness ofthe mixture which is fed to the induction of a motor coupled to outlet20 of the device.

In order to make the working of the apparatus clear, it will be assumedrstly that valves 6 and 8 and ports 45 are open, as is shown in dots anddashes in Fig. 1 and in full lines in Fig. 2.

Outside air is sucked by the motor, enters the base of the carburetorbetween the arms of cruciform piece 24 and iows into the choke tube 5.When entering the latter, it is divided into two concentric streams ofwhich the iirst, or primary, passes within conical valve 6 and thesecond, or auxiliary, flows into the annular space comprised betweencone 6 and choke tube 5. The primary air stream, to which a high speedis imparted by the narrowness of the inner channel of cone 6, carriesthe thin annulus of fuel standing ush with mouth 3 of jet 4 on topoint-stein 2a, thence on to point 2 and on to spreader cone 1, throughports 45. The gap formed by groove 33 sets up, behind the point-stem 2a,a vacuum which assists in sucking fuel from the jet.

Upon leaving ports 45, the fuel-charged primary air'stream joins theauxiliary air stream and both spread the fuel upon cone 1 in a lm ofprogressively decreasing thickness until it is vaporized. The mixture offuel and air thus made impinges, beyond the cone, against stationary,inclined and specially shaped vanes 46 (Figs. 1 and 4), which cause itto whirl, in which condition it enters the auxiliary choke tube 9,passes round deflector 8 and flows towards outlet 2O and the inductionmanifold of the engine.

Vanes 46, which may be integral with a disc 47 supporting spreader cone1, are held by hollow screws 48, by means of which these two members aresuspended from the inner wall of the reheating jacket 12. Said screwsbeing hollow also serve to connect said jacketY with an inner cavity 49of cone l. On the other hand, jacket 12 communicates by means of ducts50 with a jacket 51, surrounding choke tube 5, so that the Warming fluidentering through pipe 52 and discharging through pipe 53 iows, not onlywithin jacket 12, but within cone 1 and jacket 51 likewise. The mixtureof air and fuel is thus reheated from all sides, whilst flowingthroughthe carburetor.

It will be clear that the quantity of air and fuel admitted to themotor, and consequently the running of the latter, may beregulated byvarying the position of valves 6 and 8 by means of control lever 43.When said parts are in the upper position indicated in full lines inFig. 1, which corresponds with slow or idle running of the motor,

deflector 8 almost wholly closes outlet 20 and thus throttles the motorinduction, whilst Valve 6 wholly closes the mouth of choke tube 5,cutting off auxiliary air. A small amount of primary air can alone passthrough ports 45, which are almost ,i

entirely occluded by cone l, in which tube 38 is telescoped. f

The motor is accelerated by actuating lever 43, to the extent required,to depress delector 8 which uncovers outlet 20, tube 38 whose ports arefurther uncovered and allow the passage of a larger quantity of primaryair and Valve 6, which opens the mouth of choke tube 5, thereby allowingauxiliary air to enter. Maximum acceleration is reached when thecontrolling members are in the lower position, shown in dots and dashesin Fig. 1.

According to the type of fuel used, slow or idle running may beregulated by varying the section of the passage remaining free betweenthe deflector valve 8 when in its upper position, and the overhangingwall of auxiliary choke chamber 9, so as to strengthen or to reduceengine suction. This adjustment is effected by screwing or unl l'llA rim40 the deilector bears.

Said deflector valve 8 is adapted toslide `on tube 38 and isnormallypressed,against rim 40 by the spring 39, but if back firingshould take place, in the engine induction manifold for instance, thepressure ofthe ignited gas upon the upper face of deiiector 8 lwoulddrive the latter downward against the inlet to auxiliary choke-'chamber9, as shown at Bain Fig. 1, in which position deiiector 8 acts as acheck valve and, prevents the ignited gas from reaching the carburetorand setting re to the same. A safety valve V54opening from outlet 20 maybe provided, comprising a spring so weighted that the valve opens toallow ythe escape of the gases, should pressure withinchoke tube 9become excessive. t

As stated above, the carburetor likewise comprises automatic means forcutting off the supply of fuel from the jet, should the motorrevolveidly at high speed inspite of valves 6 and 8 being closed, whenthe motorie revolved by the road wheels of a car proceeding under`momentum or running downhill, for t example. The effect of the highdegree of vacuum created, in such a case, within the induction manifoldof the engine and within the carburetor itself, by the circumstance thatvalve 6 is wholly closedwhilst valve 8 remains slightly open, would beto draw an excessive quantity of fuel from jet 4 and to cause wastefulcon- `byan upward movement of piston 5,5 (Fig. 3).

The latter is kept depressed by a` lightspring 58 and its stroke islimited in an upward direction by van adjustable stop consisting ofv ascrew `59,

threaded into aineedle 60, which provides a seating for spring 58 andis, itself, supported centrally, by means of a crosspiece, within athreadedring 61. Above said needleO-is iitted a second, hollow, threadedneedle 62, through which are bored ports 63 connecting the interior of`sleeve 36 with the outlet 20 of the carbureton through ring 37,

whose lower portionnconstitutes a` conical seating adapted to t needle62. The position of `needie 62 in relation to needle 60 `and the` widthvof the passage left between these two members, lmay be adjusted byscrewing needle`62 more or less deeply into the inwardly threadedportion of sleeve 36.

When valves 6 and 8 are closed and the engine running idly at highrevolutions, the vacuum within outletV 20 soon becomes considerable andspreads to the interior of sleeve 36, to the extent regulated by needleand 62. `As soon as said vacuum is sufliciently strong to overcomespring 58, piston` 55 rises in sleeve 36 and carries with it needle `56,whose head 57 rises to obstruct the constricted portion of sleeve 31,thereby cutting off fuel from the jet to an extent governed by theposition of the screw-stop 59.

On the other hand, should the slowing down of the engine cause thevacuum to decrease, then spring 58 repels piston 55 and needle 56 againclears the duct of the jet. The same thing` happens when valves 6 and 8are opened1by depressing tube 38 since, in this case, the seating 64 ofring 37 moves towards needle 62, thereby throttling the passage betweenoutlet 20 and the interior of sleeve 36 and reducing or removing thevacuum which actuated piston 55. 65, provided in the base of sleeve 36,prevent the formation of a gas cushion at the `bottom of the same, whichmight impede the movements of piston 55.

To start the motor, fuel chamber 13 may be flooded by depressing oat 14`by means of ticklerpin 66. e

It is to be understood that the generant of the spreader cone 1 need notbe straight but might be constituted by any curve adapted to generate asuitably shaped body, the word cone, as used in the appended claims,being understood to cover any flaring body having a surface suitable forspreading a liquid in accordance with the principles of this invention.The invention is not, therefore, limited to the constructional detailshereinbefore described by way of example, as said details may be variedwithout departing from the scope of the appended claims.

I claim:

l. In a carburetor, the combination of aninverted cone, a jet co-axialwith said cone, said jet having an annular opening surrounding the apexof said cone, a choke tube surrounding said jet and said cone, airsupply passages connected to theinlet end of said choke tube, andannular means in said choke tube for directing a iiow of primary airacross said jet opening and a flow of secondary air around said flow ofprimary air.

2. In a carburetor the combination of an inverted cone, a jet co-axialwith said cone, said jet having an annular opening surrounding the apexof said cone, a choke tube surrounding said jet and said cone, anannular valve in said choke tube surrounding said jet said valvecri-operating with said cone to form a primary air passage and with saidchoke tube to form a secondary air passage, and means for moving saidvalve axially in said choke tube andV thereby simultaneously varying thecross-sectional areas of both said passages.

3. In a carburetor the combination of an inverted cone, a jetco-axialwith said cone, said jet having a delivery openingsurroundingthe apex of said cone, a choke tube surrounding said jet and said cone,a hollow conical valve surrounding said jet, the upper edge of saidvalve ccoperating with said cone to regulate a flow of primary airtherebetween, the lower edge of said valve co-operating with the wall ofsaid tube to regulate a flow of secondary air therebetween, a chamberconnected with the outlet end of said choke tube, a deflector valve insaid chamber, and means operatively connecting both said valves witheach other.

4. In a carburetor, the combination of an inverted cone, a jet co-axialwith said cone, said jet having a delivery opening surrounding the apexof said cone, a choke tube surrounding said jet and said cone, a hollowconical valve in said choke tube surrounding said jet, said conicalSmall ports valve being so arranged in the choke tube that in itsdepressed position two air passages are formed in said tube, one being anarrow passage between the said inner wall of valve and the jet, theother a wider -passage between the outer wall of said valve and thechoke tube, said valve being adapted to check the flow of air throughboth said passages when in its elevated position.

V5. In a carburetor the combination of an inverted cone, a jet co-axialwith said cone, said jet having a delivery opening surrounding the apexof said cone, a choke tube surrounding said jet and` said cone, a hollowconical valve surrounding said jet, said valve being adapted to checkthe Vflow of air through said tube, a chamber connected with the outletend of said choke tube, a deflector valve in said chamber, meansoperatively connecting both said valves with each other, said meanscomprising a tubular carrier mounted in an axial bore of said cone, theend of said carrier adjacent the conical valve having narrowlongitudinal ports, said ports remaining slightly open when the conicalvalve is in its elevated position.

Y 6. In acarburetor as claimed in claim 5, a spring within the tubularcarrier, said spring normally holding said carrier and both valves intheir elevated positions, and means for depressing said carrier with thevalves against the tension of said springs.

'7. In a carburetor as claimed in claim 3, spring means for allowing thedeflector valve to move towards the cone independently of the conicalvalve, and a seating adapted to receive said deiiector valve in itslowerinost position, said seating being interposed between the choketube and the outlet chamber.

8. In a carburetor as claimed in claim 5, the deector valve beingslidably mounted on its tubular carrier, an adjustable abutmentadjustably fitted at the top or" said carrier, and a coil springinterposed between the cone and the delector valve, said valve beingnormally held in contact with said abutment by said spring.

9. In a carburetor, the combination with the elements recited in claim3, with means iniiuenced bythe vacuum above the deiiector valve forcutting the supply of fuel through the jet when said vacuum exceeds agiven limit.

10. In a carburetor the combination oi an inverted cone, a jet co-axialwith said cone, said jet having a` delivery opening surrounding the apexof said cone, a choke tube surrounding said jet and said cone, a holiowconical valve surrounding said jet, said valve beinfr adapted to checkthe flow of air through said tube, a charnber connectedwith the outletend of said choke tube, a vdeiector valve in said chamber, meansoperatively connecting both said valves with each other, meansinfluenced by the vacuum above the deilector valve for cutting thesupplyof fuel through the jet when said vacuum exceeds a given limit, thevacuum iniiuenced means comprising a spring controlled piston in anaxial bore of the cone, and a member extending through the apex of thecone into the jet.

11. In a carburetor as claimed in claim 10, adjustable means for varyingthe action on the piston of the vacuum above the delector valve.

12. In a carburetor as claimed in claim 5, a spring controlled piston inthe tubular carrier, a hollow member iitted at the end of the cone, saidmember extending axially into the jet, ports in said hollow member,`said ports controlling the passage of the fuel through the jet, and aclubshaped member adjustably connected to f said piston, saidclub-shaped member extending through said hollow member, said pistonbeing subjected to the vacuum above the de'lector valve, saidclub-shaped member being adapted to close said ports when said piston isdrawn upwards by the action of said vacuum.

13. In a carburetor, the combination of an inverted cone, a jet beneathsaid cone and co-axial therewith, said cone having a downwardlyprojecting point projecting into said jet, said point forming with theupperedge of said jet an annular orifice for the delivery of liquidfuel, a

choke tube surrounding said jet and said cone, said annular oriceopening into the constricted portion of said choke tube, the inlet endof said choke tube being open to the atmosphere, an annular valve -insaid choke tube surrounding said orice, the upper edge of said valvecooperating with said cone toV direct a now of primary air across saidorifice the lower edge of said valve cooperating with said choke tube todirect a flow of secondary air around said valve, and means for varyingthe relative positions between said cone and said jet.

14. 'In a carburetor, the combination of an inverted cone, a jet beneathsaid cone and co-axial therewith, said jet having a delivery openingsurrounding the apex of said cone, a choke tube surrounding said jet andsaid cone, the inlet end of said'choke'tube being open to theatmosphere, means for varying the iiow of air through said choke tube, asuction chamber connected with the outlet end of said choke tube, andmeans infiuenced by the vacuum in said suction chamber for automaticallycutting loff the supply oi fuel through said jet.

15. In a carburetor as claimed in claim 14, the suction chamber and thecone having hollow walls respectively forming a jacket around saidsuction chamber and a jacket within said cone, tubular passagesconnecting said jacket with each other, and pipe connections forcirculating a heating fluid through' said jackets.

16. In a carburetor, the combination of an inverted cone, a jet beneathsaid cone and coaxial therewith, a choke tube surrounding said jet andsaid cone, said jet having an annular orifice for the delivery of fuel,said orice opening into the constricted portion of said choke tube, andan annular valve in said choke tube surrounding said jet, the upper edgeof said valve co-operating with said cone to form a primary air passage,the lower edge of said valve cooperating With said tube tok form asecondary air passage.

17. In a carburetor, the combination of an inverted cone, a jet co-axialwith said cone, said jet having an annular opening underneath said cone,a choke tube surrounding said jet and said cone, the inlet end of saidtube being connected with the atmosphere, an annular valve in said choketube surrounding said jet, the upper edge of Asaid valve co-operatingwith said cone to form a primary-air passage, the lower edge of saidvalve co-operating with said tube to form a secondary air passage, meansfor depressing said valve, the arrangement being such that on saidvalvebeing depressed the cross-sectional area of said secondary airpassage increases more rapidly than that of said primary air passage.

18. In a carburetor, the combination oi an inverted cone, a jet beneathsaid cone and co-axial therewith, a choke tube surrounding said jet andsaid cone, the inlet end of said choke tube being open to theatmosphere, said jet having an annular orice for the delivery of fuel,said oriiice opening into the constricted portion of said choke tube,means in said choke tube for dividing the air owing therethrough into aiiow of primary air sweeping across said orice and a flow of secondaryair surrounding said flow of primary air, and means for imparting awhirling motion to the air issuing from said choke tube.

ANDRE MATHIEU.

